1. Field of the Invention
This invention is directed to X-ray lithography masks, in general, and to a mask having the X-ray absorber material embedded in the mask, per se.
2. Prior Art
There are many known masks which have been produced for use with X-ray lithography techniques. The known masks generally comprise a thin supporting membrane which is transparent to X-rays, a patterned absorber layer of dense material which is substantially opaque to soft X-rays supported on the membrane, and mechanical support means such as a peripheral ring bonded to the membrane.
The known masks noted above are typically fabricated in a sequence wherein a membrane is bonded to a support ring, the membrane is coated with an absorber layer (for example heavy metal), and the absorber is patterned using suitable lithography and/or etching steps.
However, the known masks and methods of making same are not totally satisfactory. That is, in the known masks the patterned absorber typically protrudes above the membrane surface leading to problems with mechanical damage and/or wear as well as significant problems with adhesion of contamination and particulate matter. More importantly, however, the known masks and method require that the absorber material be deposited in such a manner that, when patterned, non uniform strain in the thin membrane occurs.